Territory



(N0 Model.) 2 Sheets Sheet 1.

G. A, BROWN.

PLOTTER.

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UNITED STATES PATENT OFFICE.

GEORGE A. BROWVN, OF PARK CITY, UTAH TERRITORY.

PLOTTER.

SPECIFICATION forming part of Letters Patent No. 444,312, dated January 6, 1891.

Application filed April 5, 1890. Serial No. 346,768. (No model.)

To all whom it may concern:

Be it known that I, GEORGE A. BROWN, residing at Park City, in the county of Summit and Territory of Utah, have invented certain new and useful Improvements in Drawing-Instruments, of which the following is a specification.

My invention has for its object to provide a suitably-constructed drawing-instrument which will serve as a combined T-square and protractor, whereby the same can be readily adapted for architectural or surveyors uses.

My invention consists in providing a suitable base-plate or ruler adapted to be held in any suitable manner upon a drawing board or table having a longitudinal rack gear groove, a T-square provided with a base-plate a apted to be slid onto the said ruler for longitudinal movement thereon, providing such T-square base with a longitudinal shaft carrying worm gear or gears adapted to engage the groove in the ruler-base, and providing suitable operating thumb-screws whereby said T-square can be moved across the drawing-board in either direction to predetermined positions.

It also consists in forming the T-square blade with a suitablyarranged rackgear groove adapted to receive suitably-constructed gearing devices held on the base of a protractor, and providing said protractor with a blade and with suitably-arranged thumb-opcrating knobs, whereby said protractor may be adjusted to the positions required in relation to the T-square blade. 7

My invention finally consists in: the sundry novel arrangement and peculiarcombination of parts, all of which will hereinafter be fully described in the annexed specification, and particularly pointed out in the claims, reference being had to the accompanying drawings, in which Figure l is a plan view of my improved drawing-instrument, showing same adapted for architectural uses. Fig. 2 is a similar view showing same as adapted for surveyors uses. Fig. 3 is an end view looking in the direction indicated by the arrow. Fig. 4 is a cross-section on the line 4 4, Fig. 1; and Fig. 5 is a similar view taken on the line 5 5, Fig. 2.

In the accompanying drawings, A indicates a metal plate formed with straight edges, provided with the usual inches and metric scales, as shown at a and b, respectively. The upper face of the plate A is formed with a semicircular longitudinal groove B, the base of which is formed with a recess 1) and the side Walls thereof with obliquely-arranged rackteeth 0, as shown, the recess 1) serving to take up the dirt or dust which might collect in the groove B, thereby admitting of the same being quickly brushed out. The upper face of the lower part of the plate A is also provided with a longitudinal groove a, and the upper edge of the groove portion B of the plate is formed with tongues b 11 which fit into grooves (1 cl, formed in the head D of the T-square D, said head being also provided with a rib (1 which fits the groove a.

E denotes a shaft journaied in the head D of the T-square in elongated bearings 10 formed therein, whereby said shaft is adapted for slight vertical movement for a purpose presently explained. One or more wormwheels E E are held on said shaft to turn therewith, the lower faces of which normally seat in the curved teeth G in the groove 13, said shaft being also provided with a cogwheel G, which meshes with a cog-wheel II on a shaft I, arranged parallel with and over the shaft E, said shaft being also journaled in the head D for a slight vertical movement.

Upon the outer ends of the shafts E and I are secured indicator-wheels J and K, one of which J is provided with a series of graduations j and with a second series j',the wheel K being also provided with a series of graduations k, as shown. By reference to Fig. 3

of the drawings it will be seen thatl arrange four marks j, forming the wheel into quartersections, and three marks j, forming said wheel into three sections, the wheel K being divided into quarter-sections, as shown at It. The relation of the shaft E and its wheel K to the rack-groove B is such that a complete revolution of the said shaft willcanse the T- square to be moved one-fifth of an inch, and each quarter movement thereof one-twentieth of an inch.

As it is intended that a complete revolution of the shaft I shall move the T-square one-fourth of an inch, I provide the cog-gear G with twenty teeth and then make the gear II on the shaft I of a proportionately larger size and provide same with twenty-five teeth. By this construction it will be seen that one complete revolution of the shaft I will cause the T-square to be moved one-fourth of an inch, and each quarter-revolution one-sixteenth of an inch.

As it sometimes is desirable to draw parallel lines but one-twelfth of an inch space apart, I therefore also provide the wheel J with the thirds divisions, as stated. Each one-third of a revolution of the wheel J will indicate aspace of one-twelfth of an inch.

At the outer edges of the several grad uation-marksjj and k the wheels J and K are formed with notchesl I, with which engage suitably-arranged spring-latches I. L, which serve to automatically look into the several notches and hold the T-squarefrom being accidentally moved too far.

It will be understood that the several quarter-sections on the wheels J and K can be subdivided to halves, quarters, &e., and the T-square adjusted to draw parallel lines spaced to any degree desired.

Any suitable means for operating the shaft E may be employed; but I prefer the construction shown in the drawings, which consists in extending the shaft I and providing the same with a thumb-knob M.

In operation, when used for architectural purposes, the operator gages the movem cut by the upper disk, the movement of the Tsquare being indicated thereon, and each space on the disk being subdivided into halves and quarters admits of the T-square being moved to any extent desired without the necessity of the draftsman using dividers and the like to indicate the proper points.

When it is desired to shift the T-square on the base-plate A to remove same therefrom or when detached to slip it in position, I provide a rod and link N, which is looped under the shaft E, the upper end of which is connected to the inner end of a springactuated thumb-lever disposed on the upper face of the head D. By depressing said thumb-lever the link N will lift the shaft E in its bearings and hold the worm-gears F outof engagement with the groove B, thereby permitting of a free movement of said head. The straight edge of the T-square blade is also provided with a central groove D, which is fitted with a longitudinal recess and curved rack-teeth similar to the groove 13 and with longitudinal grooves d d, in which tongues 19 p on a base-plate P fit, said plate being further held on the blade D by the tongueandgroove connection 11' and 12 In elongated bearings formed on said base-plate is journaled a shaft R, which is provided with worm-gears Q, which normally mesh with the rack-teeth in the groove D said shaft being also provided with a cog-wheel S, with which meshes a cog-wheel '1, held on the under face of a bracket 1- of the plate P, the upper end of the shaft of such wheel being provided with asuitable thumb-nut T, as shown, by the adjustment of which the protractor can be adjusted longitudinally on the T-square blade, as desired.

The protractor \V consists of the blade \V' and the head \V said head being formed, preferably, by bifurcating the rear end of the blade, as at w, and extending the upper portion over the baseplate P and under the shaft, said extension 10 being formed into a protractor-plate having the usual graduated scale thereon, said plate being cut away, as shown in Fig. 2, whereby an annular ring portion to is provided, the inner edge of which is formed with a series of teeth L0 with which meshes a pinion X, mounted on a short shaft .70, journaled in the base-plate, the upper end of which projects above the protractor-plate and is provided with a suitable thumb-piece X, as shown. The base-plate I is also provided with a short upward extension having graduations upon its face, which serve as a guide for setting the protractor-plate to its normal position.

By the above-described construction it will be seen that by turning the thumb-nut 'l the plate P and the protractorcan be adjusted longitudinally on the T-square blade D and when set to its proper position on the blade D the protractor-blade can be swung to an acute or obtuse angle to the blade D by turning the shaft: 00 and the pinion X, and when adjusted to the angle desired the protractor can be held in such position by tightening the nut Y through the medium of the thumb piece Y. (See Fig. 5.) Vthen it is desired to remove or slide the protractor along the blade I) rapidly, by pressing on the thumblever Z which is constructed similar to the lever, the worm-wheels will be held from contact with the rack-groove gears.

The protractor-blade is provided with the usual graduations on its straight edges, as shown. The lower face of the blade is concaved its entire length, excepta portion 10, which extends inward to the eenterof the blade in line with the pivotal axis of the blade, a 1011- gitudinal slot 20 being formed. By this arrangement it will be seen that the draftsman can obtain any angle he desires by adjusting the edge 30 in line with the axis, and after marking the desired angle on the paper he can adjust the protractor on the blade D so as to make lines parallel on the same angle, if desired.

A A denote stopplates secured upon the blade I), which are adapted for adjustment thereon, the edges thereof projecting over the edges of the blade D". By spacing these stop-plates to the proper distances on the blade I) the length of the lines to be drawn will be determined thereby.

From the foregoing description, taken in connection with the drawings, the advantages and operation of my invention will be readily understood by those skilled in the art to which it appertains. The same is exceedingly simple in construction and its operation sure and positive, it supplying an instrument by the use of which the trouble, anxiety as to the proper dimensions, and loss of time in computing and making measurements in the usual manner incident to architectural or surveyors work are reduced to a minimum.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. An improved drawing-instrument comprising a fixed base-plate, a T-square held for longitudinal movement thereon, and a protractor adapted to be detach ably connected to the blade of said T-square and have 1011- gitudinal movement thereon, substantially as shown and described.

2. An improved T-square consisting of a base-plate adapted to be held upon the drawing board or table, provided with a longitudinal rack in its upper face, a T-square formed with a head portion D, held to slide on said base, a shaft journaled in said head D, provided with worm-gears adapted to engage the longitudinal rack in the base-plate, an indicator-wheel held on said shaft, and means for operating said shaft, substantially as and for the purpose described. v

3. Animproved T-square comprising a baseplate having a longitudinal rack-groove, a T- square portion formed with a head D, held to slide 011 said base-plate, a shaft journaled in said head, provided with worm-gears engaging the longitudinal rack-groove in the baseplate, a second shaft mounted in said head, differential gear-connections between said shafts and indicator-wheels mounted on the ends of said shafts, and means for operating said shafts, as shown, said wheels adapted to indicate the degrees of movement of said T- square in relation to the base-plate, substantially as and for the purpose described.

4. An improved T-square comprising the baseplate A, having a longitudinal rackgroove in its upper face, the T-square portion D, formed with a head D, detachably held to slide on said plate A, a shaft journaled with slight vertical movement in said head, having worm-gears adapted to engage said longitudinal rack-groove in the base-plate, means for rotating said shaft, whereby said head D is moved graduallyin longitudinal directions on said base-plate, and the lifting mechanism, substantially as shown, for raising said wormgears from contact with the said rack-groove, whereby said head D can be quickly moved on the base-plate, substantially as shown and described.

5. The combination, with the base-plate A and the T'-square D, held for longitudinal movement thereon, of a protractor held for longitudinal movement on the T-square blade D and means for moving said protractor at angles to said blade, substantially as and for the purpose described. 1

6. The combination, with the T- square blade D formed with a longitudinal rackgroove, a head P, having worm gearing mounted therein, adapted to engage said groove, and means for rotating such wormgears, whereby said head is moved longitudinally on said blade, of a protractor held over said head and having a pivotal connection therewith and means for adjusting said protractor at angles to the blade D substantially as and for the purpose described.

7. The combination, with the T-square D, formed with a longitudinal rack-groove on its upper face, a head P, held to slide thereon, a shaft journaled therein having worm-gears adapted to engage the rack-groove in the blade D and means for rotating said shaft, as shown, of a protractor held over said plate P and pivotally connected therewith, said protractor formed with a blade having an elongated opening, one wall of which is in line with the pivotal axis of said protractor, and the gear mechanism for adjusting said protractor on its pivot, substantially as shown and described.

GEO. A. BROWN.

Witnesses:

SoLoN C. KEMON, CHAS. A. PETTIT. 

